Since the HP Prime is able to handle strings, is it possible to take strings and convert them into functions? I know back in the TI-85 there was such a command. Does/will the HP Prime have the ability to ask users to input a function to be used as a symbolic object like equations in the HP48 series?

I tried using the INPUT command but it seems to only accept numerical inputs.

Thank you for sharing your example, Namir. What I was looking for in particular, however, was an example on how to use INPUT in order to get a function. My goal is to create an interactive app, as opposed to a function like yours in which everything is entered at once. My attempt below results in an input-form-like interface (much like the HP48 series) but the default value is 0, and not a formula.

EXPORT EXAMPLE()
BEGIN

INPUT(F,"Graph 3D","f(x,y)=","Enter the function to graph","1/390*(X^3*Y-X*Y^3");

END;

If I do enter a new formula "X*Y" or 'X*Y' -- with the quotes -- I get a syntax error. If I take out the quotes, then (as expected), the value of F is whatever X*Y is equal to the moment the program was run. However, this is not what I want, since I cannot evaluate F at different values of X and Y later within my program.

Secondly, if such a procedure should work, then presumably F is a string. How would I then convert a string object into a function?

Quote:
INPUT allows all type of argument but you have put the right delimiters:

" "

[ ]

{ }

etc.

be carefull that A..Z variables are only numericals

The INPUT command is very powerfull (default value, on line help ...)

To clarify, I was not referring the the arguments of the INPUT command. Instead the INPUT command -- when in use -- seems to only allow the user to enter in numerical values when the program is running.